Development of a targeted forensic test for the identification of Eurasian beaver DNA

Eurasian beaver (Castor fiber) has recently been reintroduced in Scotland after more than 400 years of extinction and in 2019 received legal protection; deliberate killing or disturbing beavers without a license is therefore now an offense. We present a validated polymerase chain reaction (PCR)-based Eurasian beaver identification test for use in forensic casework where persecution of Eurasian beaver is suspected. Primers were designed to target a 271 base pair region of the mitochondrial cytochrome b (Cytb) gene in Eurasian beavers, and positive amplicons were confirmed by sequence analysis. Validation was carried out across two laboratories in Scotland, and included studies on sensitivity, specificity, reproducibility, and robustness. The developed test reliably detects Eurasian beaver DNA to the lower limit of 0.1 pg DNA input and differentiates Castor fiber from other species, including congeners. In conclusion, the developed test was successfully optimized and validated to identify Eurasian beaver DNA and will be a valuable tool in wildlife forensic laboratories in cases of suspected persecution of Eurasian beavers.